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Articles 31 - 34 of 34
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Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project was designed to study the N fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) as influenced by location and climate. Multiple rates of fertilizer N are spring applied, with the intent to measure yield response to N within each rotation on a yearly basis for multiple years at multiple sites across Iowa. This will allow the determination of N requirements for each rotation practice, differences that exist between the two rotations, responses to applied N across different soils and climatic conditions, and evaluation of tools used to adjust N application.
Revised Alfalfa Fertilizer Recommendations For A Changing Environment Greatly Improves Profitability, Brian Lang, John E. Sawyer, Daniel Barker, Ken Pecinovsky
Revised Alfalfa Fertilizer Recommendations For A Changing Environment Greatly Improves Profitability, Brian Lang, John E. Sawyer, Daniel Barker, Ken Pecinovsky
John E. Sawyer
During the last decade, an ever-increasing percentage of alfalfa fields in northeast Iowa have been exhibiting signs of reduced growth and vigor, resulting in declining profitability. Iowa State University Extension in northeast Iowa initiated an investigation into this problem. Sixteen research trials conducted in northeast Iowa over the next 6 years as both on-farm trials and at the northeast ISU research farm uncovered widespread sulfur deficiency problems in alfalfa production. Over 90 ISU Extension educational meetings in northeast Iowa, and extensive use of the media, communicated this issue and tools to address it to farmers and agricultural providers. Survey results …
Phosphorus And Potassium In Silage Harvest Of Drought-Damaged Corn, John E. Sawyer, Antonio P. Mallarino
Phosphorus And Potassium In Silage Harvest Of Drought-Damaged Corn, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
The dry conditions this summer are resulting in quite variable corn growth and production potential. Some livestock producers are beginning harvest of corn damaged by drought conditions for silage. Corn silage harvest results in more phosphorus (P) and potassium (K) removal than grain alone because almost the entire plant is harvested. The increased amount removed with silage differs for P and K because the relative amount of P and K is different in corn vegetative parts than in grain. For P there can be approximately four times greater amount of P per ton of dry matter in grain than vegetative …
Nitrogen Loss: How Does It Happen?, John E. Sawyer
Nitrogen Loss: How Does It Happen?, John E. Sawyer
John E. Sawyer
For the period April 1 through May 6, 2007, much of Iowa received more than 5 inches of rainfall (May 6, 2007 AWIS Inc. report). The Northwest, North-Central, and East-Central districts averaged slightly less than 5 inches, and the West-Central and Southwest districts more than 9 inches. With the large rainfall and flooding conditions, many producers are wondering about nitrogen (N) losses. While this period certainly has an influence on N in the soil, excessively wet conditions later in the spring are especially important for N losses. Early to mid-June will be a critical period to assess crop growth and …